The quark propagator lies at the core of lattice hadron spectrum calculations as well as studies ... more The quark propagator lies at the core of lattice hadron spectrum calculations as well as studies in other nonperturbative schemes. It manifestly displays dynamical chiral symmetry breaking and can be used to connect nonperturbative methods with perturbation theory. ...
Non-Perturbative QCD - Proceedings of the Sixth Workshop, 2002
Lattice-based investigations of two fundamental QCD quantities are described, namely the gluon an... more Lattice-based investigations of two fundamental QCD quantities are described, namely the gluon and quark propagators in Landau gauge. We have studied the Landau gauge gluon propagator using a variety of lattices with spacings from a = 0.17 to 0.41 fm to explore finite volume and discretization effects. We also introduce the general method of "tree-level correction" to minimize the effect of lattice artefacts at large momenta. We demonstrate that it is possible to obtain scaling behavior over a very wide range of momenta and lattice spacings and to explore the infinite volume and continuum limits of the Landau-gauge gluon propagator. These results confirm the earlier conclusion that the Landau gauge gluon propagator is infrared finite. We study the Landau gauge quark propagator in quenched QCD using two forms of the {\cal O}( a ; )-improved propagator with the Sheikholeslami-Wohlert quark action with the nonperturbative value for the clover coefficient csw and mean-field improvement coefficients in our improved quark propagators. We again implement an appropriate form of tree-level correction. We find good agreement between our improved quark propagators. The extracted value of infrared quark mass in the chiral limit is found to be 300 ± 30 MeV. We conclude that the momentum regime where the transition from nonperturbative to perturbative QCD occurs is Q2 ~= 4 GeV2.
Quark Confinement and the Hadron Spectrum V - Proceedings of the 5th International Conference, 2003
THE NONPERTURBATIVE QUARK-GLUON VERTEX* JONIVAR SKULLERUD* Instituut for Theoretische Fysica, Uni... more THE NONPERTURBATIVE QUARK-GLUON VERTEX* JONIVAR SKULLERUD* Instituut for Theoretische Fysica, University of Amsterdam Valckenierstraat 65, 1018 XE Amsterdam, The Netherlands Email: jonivar@ skullerud. name PATRICK BOWMAN AND AY § E KIZILERSU Centre for ...
Shape of the proton in a uniform magnetic field. [AIP Conference Proceedings 1261, 135 (2010)]. D... more Shape of the proton in a uniform magnetic field. [AIP Conference Proceedings 1261, 135 (2010)]. Dale S. Roberts, Patrick O. Bowman, Waseem Kamleh, Derek B. Leinweber. Abstract. The effect of a uniform background magnetic ...
The properties of the quark propagator in Landau gauge in quenched QCD are examined for the overl... more The properties of the quark propagator in Landau gauge in quenched QCD are examined for the overlap quark action. The overlap quark action satisfies the Ginsparg-Wilson relation and as such provides an exact lattice realization of chiral symmetry. This in turn implies that the quark action is free of ${\cal O}(a)$ errors. We present results using the standard Wilson fermion
The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau gauge in the asympto... more The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau gauge in the asymptotic limit. Like Landau gauge, it respects Lorentz invariance, but it is free of Gribov copies; the gauge fixing is unambiguous. In this paper we study the infrared behavior of the lattice gluon propagator in Laplacian gauge by using a variety of lattices with spacings
Proton Wave Functions in a Uniform Magnetic Field. [AIP Conference Proceedings 1354, 224 (2011)].... more Proton Wave Functions in a Uniform Magnetic Field. [AIP Conference Proceedings 1354, 224 (2011)]. Dale S. Roberts, Patrick O. Bowman, Waseem Kamleh, Derek B. Leinweber. Abstract. The wave function of the d‐quark in the ...
The quark propagator lies at the core of lattice hadron spectrum calculations as well as studies ... more The quark propagator lies at the core of lattice hadron spectrum calculations as well as studies in other nonperturbative schemes. It manifestly displays dynamical chiral symmetry breaking and can be used to connect nonperturbative methods with perturbation theory. ...
Non-Perturbative QCD - Proceedings of the Sixth Workshop, 2002
Lattice-based investigations of two fundamental QCD quantities are described, namely the gluon an... more Lattice-based investigations of two fundamental QCD quantities are described, namely the gluon and quark propagators in Landau gauge. We have studied the Landau gauge gluon propagator using a variety of lattices with spacings from a = 0.17 to 0.41 fm to explore finite volume and discretization effects. We also introduce the general method of "tree-level correction" to minimize the effect of lattice artefacts at large momenta. We demonstrate that it is possible to obtain scaling behavior over a very wide range of momenta and lattice spacings and to explore the infinite volume and continuum limits of the Landau-gauge gluon propagator. These results confirm the earlier conclusion that the Landau gauge gluon propagator is infrared finite. We study the Landau gauge quark propagator in quenched QCD using two forms of the {\cal O}( a ; )-improved propagator with the Sheikholeslami-Wohlert quark action with the nonperturbative value for the clover coefficient csw and mean-field improvement coefficients in our improved quark propagators. We again implement an appropriate form of tree-level correction. We find good agreement between our improved quark propagators. The extracted value of infrared quark mass in the chiral limit is found to be 300 ± 30 MeV. We conclude that the momentum regime where the transition from nonperturbative to perturbative QCD occurs is Q2 ~= 4 GeV2.
Quark Confinement and the Hadron Spectrum V - Proceedings of the 5th International Conference, 2003
THE NONPERTURBATIVE QUARK-GLUON VERTEX* JONIVAR SKULLERUD* Instituut for Theoretische Fysica, Uni... more THE NONPERTURBATIVE QUARK-GLUON VERTEX* JONIVAR SKULLERUD* Instituut for Theoretische Fysica, University of Amsterdam Valckenierstraat 65, 1018 XE Amsterdam, The Netherlands Email: jonivar@ skullerud. name PATRICK BOWMAN AND AY § E KIZILERSU Centre for ...
Shape of the proton in a uniform magnetic field. [AIP Conference Proceedings 1261, 135 (2010)]. D... more Shape of the proton in a uniform magnetic field. [AIP Conference Proceedings 1261, 135 (2010)]. Dale S. Roberts, Patrick O. Bowman, Waseem Kamleh, Derek B. Leinweber. Abstract. The effect of a uniform background magnetic ...
The properties of the quark propagator in Landau gauge in quenched QCD are examined for the overl... more The properties of the quark propagator in Landau gauge in quenched QCD are examined for the overlap quark action. The overlap quark action satisfies the Ginsparg-Wilson relation and as such provides an exact lattice realization of chiral symmetry. This in turn implies that the quark action is free of ${\cal O}(a)$ errors. We present results using the standard Wilson fermion
The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau gauge in the asympto... more The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau gauge in the asymptotic limit. Like Landau gauge, it respects Lorentz invariance, but it is free of Gribov copies; the gauge fixing is unambiguous. In this paper we study the infrared behavior of the lattice gluon propagator in Laplacian gauge by using a variety of lattices with spacings
Proton Wave Functions in a Uniform Magnetic Field. [AIP Conference Proceedings 1354, 224 (2011)].... more Proton Wave Functions in a Uniform Magnetic Field. [AIP Conference Proceedings 1354, 224 (2011)]. Dale S. Roberts, Patrick O. Bowman, Waseem Kamleh, Derek B. Leinweber. Abstract. The wave function of the d‐quark in the ...
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